You can keep track of multiple counters at once and organize them into "Counting Boards". Choose how much to count by ("step") and what to start at. Negative and non-whole numbers are supported. Numbers can be very large. You can also convert numbers to tallies (integers 1-99,999). There are various settings. The full version has a home screen widget and exclusive customization features.

Lite Version Features
• Keep track of multiple counters on multiple counting boards
• Convert numbers to tallies
• Counter step size and starting point options
• Option to use volume buttons to count
• Export and import counters in settings menu

Extra Full Version Features
• 5 theme choices: Auto, Dark, Light, Black Out, and Light Amber
• Counter widget for your home screen
• Change color of counters
• Field to type in current counter steps

Full Version Link
https://play.google.com/store/apps/details?id=com.grantojanen.counter

More Details
Offline: Yes
Lightweight: Yes, < 1MB
Multi-Window Support: Yes